OFFSET
1,1
COMMENTS
Dence and Pomerance showed that the asymptotic number of the terms below x is ~ x.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
Thomas Dence and Carl Pomerance, Euler's function in residue classes, in: K. Alladi, P. D. T. A. Elliott, A. Granville and G. Tenenbaum (eds.), Analytic and Elementary Number Theory, Developments in Mathematics, Vol. 1, Springer, Boston, MA, 1998, pp. 7-20, alternative link.
EXAMPLE
13 is a term since phi(13) = 12 == 0 (mod 12).
MATHEMATICA
Select[Range[200], Divisible[EulerPhi[#], 12] &]
PROG
(Magma) [k:k in [1..170]| EulerPhi(k) mod 12 eq 0]; // Marius A. Burtea, Feb 14 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Feb 14 2020
STATUS
approved